1. Technical Field of the Invention
A method of forming a metal wiring in a semiconductor device. More particularly, the present invention relates to a method of forming a metal wiring in a semiconductor device by which deposition of copper is accelerated by use of a chemical enhancer layer and the chemical enhancer layer is removed after deposition of the copper. Further, process technology is disclosed by which a damascene pattern of an ultra-fine structure is filled with copper using a copper precursor, thus maximizing an electrical characteristic of a copper wiring.
2. Description of the Prior Art
Recently, although aluminum has been used a a metal wiring material in a semiconductor device, there has been recent study of a two-step process by which a titanium thin film is deposited and aluminum is then deposited by means of physical vapor deposition (PVD) method and chemical vapor deposition (CVD) method. On the other hand, when copper is used as a metal wiring, a method is employed by which copper is deposited by means of electroplating method using Ta or TaN as a diffusion prevention film of copper, which is deposited by PVD method. In both cases, however, there are limitations in that the next-generation ultra-fine wiring structures require good step coverage and a good filling of contact due to increased aspect ratio. As one solution to this limitation, a chemically enhanced chemical vapor deposition (CECVD) method is used to fill a damascene pattern using various chemical enhancers that can accelerate deposition of copper. However, due to high electrical resistivity of various chemical enhancers accelerating deposition of copper, there is a problem that it undermines the purpose of employing a copper wiring having a low electrical resistance.
A method of forming a metal wiring in a semiconductor device is disclosed by which the deposition speed of copper is accelerated using a chemical enhancer layer but the chemical enhancer layer rises to the surface of copper and is removed by means of plasma process after deposition of copper, thus preventing an increase in the electrical resistance of the copper wiring due to high resistivity of the chemical enhancer.
The method of forming a metal wiring in a semiconductor device according to the disclosure is characterized in that it comprises: providing a semiconductor substrate in which an insulating film having a damascene pattern is formed; forming a diffusion prevention film on the insulating film; forming a copper seed layer on the diffusion prevention film; forming a chemical enhancer layer on the copper seed layer; forming a copper layer by means of chemical vapor deposition method; removing the chemical enhancer layer risen to the surface of the copper layer, by plasma process; and completely filling the damascene pattern by copper electroplating method, and then forming a copper metal wiring by performing a hydrogen reduction annealing process and a chemical mechanical polishing process.